package jdbc;

import java.io.IOException;
import java.io.InputStream;
import java.sql.*;
import java.util.Properties;

/**
 * JDBC工具类
 */
public class JDBCUtils {
    private static String url;
    private static String user;
    private static String password;
    private static String driver;

    //文件的读取，只需要读取一次即可拿到这些值。使用静态代码块
    static {
        try {
            //1. 创建Properties集合类。
            Properties pro = new Properties();
            //获取src路径下的文件的方式--->ClassLoader 类加载器
            ClassLoader classLoader = JDBCUtils.class.getClassLoader();
//            URL res = classLoader.getResource("jdbc.properties");//一定要在src下面
//            String path = res.getPath();
//            pro.load(new FileReader(path));

            InputStream is = classLoader.getResourceAsStream("jdbc.properties");
            pro.load(is);
            // System.out.println(path);///D:/IdeaProjects/cn.itcast/out/production/day04_jdbc/jdbc.properties
            //2. 加载文件
             //pro.load(new FileReader("D:\\IdeaProjects\\cn.itcast\\day04_jdbc\\src\\jdbc.properties"));
            //3. 获取数据，赋值
            url = pro.getProperty("url");
            user = pro.getProperty("user");
            password = pro.getProperty("password");
            driver = pro.getProperty("driver");
            //4. 注册驱动
            Class.forName(driver);

        } catch (IOException e) {
            e.printStackTrace();
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
    }

    /*public static void close(Statement stmt, Connection conn) {
        if (stmt != null) {
            try {
                stmt.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }

        if (conn != null) {
            try {
                conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }*/

    //获取连接
    public static Connection getConnection() throws SQLException {

        return DriverManager.getConnection(url, user, password);
    }

    //释放资源
    public static void close(ResultSet rs, Statement stmt, Connection conn) {
        if (rs != null) {
            try {
                rs.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }

        if (stmt != null) {
            try {
                stmt.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }

        if (conn != null) {
            try {
                conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}
